CA1150960A

CA1150960A - Absorption refrigerator boiler construction

Info

Publication number: CA1150960A
Application number: CA000374918A
Authority: CA
Inventors: Peter E. Blomberg; Karl G. Boren; Axel H. Ostergren
Original assignee: Electrolux AB
Current assignee: Electrolux AB
Priority date: 1980-04-15
Filing date: 1981-04-08
Publication date: 1983-08-02
Also published as: SE422107B; SE8002803L; BR8102121A; IT1170886B; US4362029A; CH653763A5; AU6916181A; IT8148266A0; JPS56160568A; JPS622672B2; AU540350B2

Abstract

A B S T R A C T
A single-pipe boiler construction in an absorption refrigerating apparatus which operates with inert gas, an absorption solution that is rich in refrigerant. The latter is lifted in a central pump pipe in which vapor is expelled and the weak solution thus formed flows downwardly in an outer pipe. At least one heat source is arranged in heat-conductive contact with the outside of the outer pipe and heat from the heat source is conducted through the weak solution in the outer pipe to the pump pipe and its contents.
Heat is supplied directly by conduction to the outer pipe and a direct heat-conductive connection is arranged between the outer pipe and the pump pipe.

Description

~L~59:~6~

Ttli s ; nvention rel.ates to a single-pi pe boiler construction i.n an absorpt; on refrlgerating apparatus that operates with inert gas and in which the absorpt;on solution, rich in refrigerant, is lifted in a central pump pipe and 5 vapor is expelled therefrom, and the wealc solution thus formed flows downward:Ly i n an outer pipe . At least one heat source is arranged in heat-conduct:ive contact with the outer pipe, and heat from the heat source is conducted through the weak solution in the outer pi,pe to the pump pipe and 1() its contents.
Upon starting a colcl apparatus Qf this type, the temperature in the boiler rises to a value cons iderabIy above the normal. temperature o~ operation upon occasion. 'rhi.s has a]so been observed when starting an apparatus which hcls been 1.5 switchecl off for some hours.
Such abnornlally hi.i~h boi ler ten~peratures i.nvolve the r:i.sk that corrosion-protecting conlponel-lts, sllch as a type o:E chronlcltes, .~d ~ (l to the sol.ut i on are consulnecl i n a ~shorter pe!riocl of time th.ln what i s consi(lere(l to ~)e ;~() norllla]It has l~urther t urlle(l out t llat the st.lrt ol: ttle puml)-in~ 01~ l. i clui.(l jTI the Pllll~ CIOeS not t)er in Int i 1 the tenl-perature ol' operation in tt-)e outer pil)c~ has l)een surpassescl to a cons.iclernhle extellt. tn adclition to the disaclvclntareous influellce on the cool ing cal).lc;ty o~ the refri~erati.n~
apparatus the above-n~elltionecl disadvantages can negative:Ly affect the life of the apparatus.
The high temperature in the outer pipe ancl the pump plpe is due to the fact that when the solution in the pump pipe becomes cold it obtains the same concentrat ion as the weak soluti,on outside the pump pipe. In order for ~15~

the pump to start~ the sol.ution in the pump pipe must reach its boiling temperature, which when the solution is weak is about ~0C above the operating temperture prevailing in the same pipe when rich solution is supplied from the absorber vessel.
A principal object of the present invention is to eliminate the above disadvantages and for this purpose the invention :is generally characterized in that heat is supplied directly by conduction to the outer pipe, and in that a direct heat-conductive connecti.on is arranged between the outer pipe and the purnp pipe.
The Lnventi.on will be described below with refer-ence to a boiler with liquid c:i.rculation system as shown in the drawing.
In order that the inventi.on will be more clearl.y understood, i.t will now be disclosed i.n greater detai.l with reference to the accompanying drawings, in wh:ich:
FIG. 1 is a diagrammati.c eLevati.onal view of a part of an ahsorpti.on refri.~erator showing a boiler having a l;.qu:id ci.rcul.ati.on system constructed in accordance with the teach.ings of the present i.nventi.on, ancl FIG. 2 is a Itori.æontal sectional vl.ew taken throuKh the li.nes II-II of FIG. 1.
The draw:i.ngs show d:iagrammatically a l~ui.d circul-ation system :in an absorption refrigerating apparatus havi.nga so-called single pipe boiler construction and operating with inert gas and contai.ning water, ammonia and hydrogen gas as worki.ng media. It is evident that other types o~ working media may be utilized in the present refrigerating apparatus, and since the construction and function of other ~iV$~

parts of the refri~erating apparatus of this type are well known a descr:ipt;on of the liquid circulat;on system as shown in the drawi.ngs ;s sufficient for a complete understanding of the present ;nvention.
Tne absorber vessel 10 of the apparatus contains rich absorption solution rising up to a liquid level ll and when the apparatus is ;nactive and cold the liqui.d is at the same level in a pllnip p;.pe l2 communicating by way of an inner pipe 13 in the licluid heat exchanger with the absorber vessel lO. During operati.on ri.ch solution flows from the vessel 10 through a conduit 14 and the ;.nner p:ipe 13 ancl i.s punlped through the pump 12 whiLe expell;n~ vapor. The vapor ls cond~lcted through a vapor concluit 15 to a condenser (not shown) of the apparatus whereas the liftecl I.iqu;.cl lS wh;ch ;.s now weak in refrigerant is collectecl in an outer pipe 16 surroundi.ng the pump 12. I)uri.ng operati.on a liqui.d level l7 is ma;.ntalned in the outer pipe l6. I`he liquicl rLows downwardly throllgh a rectifier 1~ an(l that part of the boiler ;.n which heat i.s sllpl)lie(l Irolll one of the lleat so(lrce of

2() the apparatu.s. I~l(;. 2 wh i ch i s a cross sectioll thro~lgtl this part of the l)oiler~ shows th outer pipe 16 o~ tl)e~ boil.er in heat concluctive con~ectioll to several t~elt s(urces which can be used al.terrlativ~ly. A sleeve 2() for an ~lectric h atirlg cartritlge 21 is conn(ctel I-y a wel(l 22 to the outer pipe~ t6.
In a sinlil.ar mal)ner alotl-el~ sleeve 23 for an eLectric heat.i.n~
cartri.dge 24 for exallpLe for a clifferent operating voltage than the cartridge 21. is also heat-conducti.vely connected to the other pipe 16 by a weld 25. The apparatus can al.so be operated by a burner for ~as or liquid fuel and in such a case the hot gases are conducted through a flue pipe 26 ~5~

wh,ich by a weld 27 is heat-conductively connected to the pipe 16.
The weak solution in the outer pipe of the boiler is conducted through an outer conduit 28 in the llquid heat exchanger and a conduit 29 to an inlet 30 at the top of the absorber 31 of the apparatus. During operation, the liquid level 17 in the boiler part is so much above the lnlet 30 in the absorber part that resistance in the flow pa~h can be overcorne and a weak sol.ution suppl;ed continuously to the absorber 31.
The weak solution supplied to the absorber 31 flows in counterflow to inert gas, which is ri.ch in refr;gerant and is supplie~ to the l.ower part of the absorber by a conclu;.t 32 frorn the ~as circulat:ion system and the vapor space 33 of the absorber vessel 10.
The pump pipe 12 is f:i.xecl in posi.tion centrally i.n the outer p;pe l6 by ~ein~ connecte(l at its l.ower part to the inner pil)e l3 in the exchan~er and hy being fix~d i.n the rectifi.er l~ by a short ir~ner l~ipe 34 whi.ch, in i.ts upper part, i.s connected to the pUlllp p i pe ancl thus forms a vapor space al~ot.lt the pipe and at the outsi.cle is ~ui(le(l hy irllpres-s;ons 35 in the outer pipe. ~ccording to the invention the outer pipe has in its Lower part a crimping 36 which extencis inwardly so much that the outer pipe is in heat-con-ductive contact with the purnp pipe l2. 'rhe crilnpi.ng 36 i.srelativel.y short and situated wi.thin a lower part of the boi,ler in the zone in which heat is suppli.ed.
Even if the pump pipe 12, upon start of an apparatus according to the lnvent;.on, should contain absorption solution of lower concentrat;on of refri.gerant than dur;.ng normal operat;on, the above-described desi,gn of the apparatus will ~lL5~

cause the heat supply to be clistributed to both l:iqui.d masses commencing from the beginning of the operation. Without lnflu-encing directly the concentration of refrigerant in the absorption solution in the outer pipe it is thus poss;ble by this si.mple means, on one hand to achieve a quicker start-up of the apparatus, and on the other hand, to prevent crea-tion of undesirable excess temperature in the boiler.
Under particularly diff-icult circumstances lt may occur that the outer pipe in the boiler does not conta:in li.quid. Consequently, the apparatus w-ill not start if the apparatus is of the known type, and intended for heat transfer through the liquid contents of the outer pipe. Instead, the temperature will rise to an unacceptable extent. The present apparatus constructed according to the present invention prevents such an undesirable occurrence.
Although a sin~le embocliment of the present inven-tion is disclosecl and described hercin, it wi.ll be apparent that variati.ons and modi.fi.cations may he made herein which fall w;.th:in the spir.i.t and scope of the present invention as def:i.ned :in the following appen(ie(i ClclilllS~

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In an absorption refrigerating apparatus having a single pipe boiler construction and that operates with inert gas in which absorption solution rich in refrigerant is lifted in a central pump pipe in which vapor is expelled and the weak solution formed therein flows downwardly in an outer pipe, at least one heat source being arranged in heat-conductive contact with the outside of said outer pipe and heat from the heat source being conducted through the weak solution in the outer pipe to the pump pipe and its contents, the improvement comprising: a first means for supplying heat directly by conduction to said outer pipe and a second direct heat-conductive connection arranged between the outer pipe and said pump pipe.

2. The arrangement as claimed in claim 1 wherein said outer pipe of the boiler is provided with a metallic heat-conductive connection between said heat supplying means and said pump pipe.

3. The arrangement as claimed in claim 2 wherein said heat-conductive connection is located within the lower part of a zone in which heat is supplied to said absorption refrigerating apparatus.

4. The arrangement as claimed in claim 3 wherein said heat-conductive connection has a height which is less than half the height of said heat source which supplies heat to said outer pipe.

5. An arrangement as claimed in claim 3 wherein the surface of said pump pipe to which heat is supplied through said outer pipe is considerably smaller than the outer pipe which delivers heat to the solution therein.

6. An arrangement as claimed in claim 1 wherein the heat-conductive connection is an inwardly deformed part of said outer pipe.